Centrifugal fan.



P. KESTNBR.

GENTRIFUGAL FAN;

APPLICATION FILED JAN.4,1908.

949,150. Y Patented Feb. 15; 1910.

PAUL KESTNEB, OF LILLE, FRANCE.

CENTRIFUGAL FAN.

Specification of Letters .Patent.

Patented Feb. 15, 1910.

Application filed January 4, 1808. Serial No. 409,255.

. tion, in explaining its nature;

'jecting. The result is that a strong a back draft.

My invention relates to an improvement in centrifugal fans having a fanchamber,

an axial intake leading into said chamber and a circumferentialdischarge. These fans, in the nature of a fan Wheel, have heretoforebeen usually constructed with long blades of equal depth surrounding thefan chamber. The customary manner of mounting these blades has been to.mount them upon a rotating frame or disk from which the blades )rojectoutwardly. \Vith long and narrow lades stays have to be provider to givethe blades the necessary rigidity and these stays are objectionable asthey create eddies and obstruct the intake of the fan. This objection isespecially true of a fan of the above character when used for thepurpose of atomizing water. Under such circumstances r-eater straincomes upon the blades of the fan and the auxiliary means employed toreinforce the blades prevents such an even or regular distribution ofwater in the fan as is necessary to insure the best results. From thepoint of View of efficiency in a fan of the above character a blade ofequal depth throughout its length is not an effective one especial] whenthe fan is rotated at a high spect. The reason for this is that the airdrawn into the chamber of the fan enters at a greatspeed and strikeswith considerable orce against the frame or disk at the back of the fanfrom which the blades are prores-. sure is formed in thatpart of theadjacent to the disk and the rear portions of the fan blades are doingthe most work while the forward portions thereof are doing but littlework and in some cases creating I have attempted with considerablesuccess to remedy the defect in the ordinary form of blade as abovenoted, by making the blades tapering from back to front, or in otherwords, making the blades deeper at their inner ends adjacent to the diskthan at the eye of the fan, and a fan having such blades is described inmy Letters Patent of the United States, No. 888,444, dated May 19, 1908.This arralwement although an improvement upon t e ordinary form of bladeof the same depth throughout, has, however, this defect: that theinterval of distance between the blades at their disk ends where theirdepth is increased, becomes too small to permit of such free passage ofair as will give to the fan a maximum efficiency.

It is accordingly the object of my present invention to make a fan inwhich the blades will require no auxiliary reinforcement or suchreinforcement as will cause eddies or interfere with the free passa e orentry of fluid into the interior or chain er of the fan.

It is the further object of my invention to so arrange oi mount theblades of the fan that a to ering arrangement of the blades of the anmay be obtained, or in other words, the fan will be provided with bladesradually increasing in de th from the intaIre or eye of the fan inwarly, while the interval of distance separating the blades will besufficiently ample to insure a free passage of air outwardly between theblades from the interior of the fan.

In the drawings :Figure 1 represents the fan in longitudinal crosssection. Fig. 1 represents a section of the fan slightly modified inconstruction, to which modification special reference will hereinafterbe made. Fig. 2 is a section on the line 2-2 of Fi 1.

Referring to the drawings :A represents the improved type offancontaining the basic principles of my invention. The fan has asupporting frame or disk at which is provided with a hub a adapted toreceive the shaft bywvhich the disk may be turned. Connecting with thisdisk and with one another are a series of blade-carrying sections (L2,a, it. These sections are independent in the sense that each sectionforms a portion of the fan complete in itself, one section beingconnected to the disk and the other sections attached to this connectingsection and to one another in succeeding order or arrangement. .Ilach ofthe sectional members (L2, a a" comprises separate annular flangeforming plates (0'' between which are interposed a series of blades (1which for the several successive sections of the fan have it graduallydiminishing radial depth, the blades of the section nearest or adpicentto the disk (1 being the deepest. In this conbeing obtained a graduallytapering effect. In'Fig. 1, h owever,'the blades of each mdividualsection are of thesame radial depth throughout so that the combinedblades while producing a tapering effect are not tapered in theindividual sections. It is also to be noted that the blades of therespective sections are so arranged that the sections shall bepreferably of the same diameter; the blades of the respective sectionsare also preferably of the same axial length. The sections are attachedto the disk and to one another by means of rivets a or other means offastening-which pass through the flanges of the respective sections. Bythus building the sections onto the disk and onto one another a fan ismade which may be rotated at high speed without the necessity of anyauxihary reinforcement, and leaving a free unobstructed entrance intothe interior or chamber of the fan. The number of blades in the severalsections vary. The section having the deepest. blades has the least innumber, the blades increasing innumber as their de )th diminishes.In-practice I prefer to make the section nearest the disk with 2stblades, the next section with 32 and the next with 48. The number ofblades may be varied, however, to meet particular requirements. Byproportioning the number of blades to the width of each blade I amenabled to so arrange that the inlet to the passage between the bladesof each secti on will not be too small to prevent a proper ingress ofair. In other words, I am enabled by making the fan in sections to studyeach section in itself as to the proportions and arrangement to give toits blades a maximum etliciency. Each section being as effective aspossible the fan as a whole will also be equally effective.

I prefer to make the fan with three sec,- tions. More sections may, ofcourse, headded, but in order not to make the fan; too.

complicated-and not to exaggerate the cost it is better to make the fanwith three-sections only. A three-section fan I have also found to bethe one best ada )ted to be used for atomizing water. pre er also toprovidethe sections of the fan with curved blades, a curved bladefurnishin a larger working area for a mean width 0 blade,

Having thus fully described my inyentlon, I claim and desire to secureby Letters Patent of the United States .1. In a centrifugal fan having afan chamber, an axial intake leading into said chamber and acircumferential discharge, the combination of a supporting frame at oneend of said chamber opposite the intake of the fan, and mounted uponsaid frame a plurality of blade-carrying sections the blades of whichsections surround said chamber of the fan and which sectionsconsuccessively arranged in sections, the blades of the respectivesections being fewer; in

number but of greater depth in each successive section from the intakeof the fan inwardly, and means for supporting said blades.

3. In a centrifugal fan having a fan chamber, an axial intake leadinginto said chamber and a circumferential discharge, the combination of asupporting frame at one end of said chamber opposite the intake thereof,and mounted on said frame a plurality of blade-carrying sections securedsuccessively to one another and to said frame,

the blades of said respective sections SUP-- rounding said chamber andwhich blades for the respective sections are fewer 1n number but ofgreater depth in each successive section from the intake of the faninwardly.

4. A centrifugal fan of the character specifiedhaving in combination asupporting frame and mounted thereon a plurality of bladed sectionssecured side by side to each'other, said sections being of substantiallythe same outside diameter, and having blades of substantially the sameaxial length, the said bladcs of the respective sections, also, beingfewer in number but.- of greater radial depth in each section insuccession from the intake of-the fan inwardly.

\ PAUL KESTNER.

' Witnesses:

' HENRI CHARRIER,

LiioN 'PECKEL.

